Enhanced persulfate-assisted photocatalytic degradation of phenol by Ag/ ZnFe2O4 composite

Effective and reasonable degradation of phenolic wastewater has important practical significance in reducing environmental pollution and ensuring water resource security. Ag/ZnFe2O4 (Ag/ZFO) photocatalysts were synthesized using the one-step solvothermal method and characterized by XRD, SEM, TEM, FT-IR, XPS, UV-vis DRS, and so on. Their photocatalytic performance for phenol degradation under visible light, assisted by persulfate (PS), was studied. The incorporation of Ag nanoparticles into ZFO significantly enhanced phenol degradation efficiency, especially 10 %Ag/ZFO showing the most remarkable improvement with 94.3 % phenol degradation in 60 min, -48.7 % higher than pure ZnFe2O4. The influence of various variables, including PS dosage, initial phenol concentration, solution pH, and common inorganic anions in water, on phenol degradation were examined systematically. The superior persulfate-assisted photocatalytic performance of 10 %Ag/ZFO, assisted by PS for phenol degradation, is primarily due to the surface plasmon resonance (SPR) effect of Ag nanoparticles, enhancing light absorption and use while inhibiting the photogenerated carriers' recombination rates. In addition, Ag nanoparticles and the Fe3+/Fe2+ recycling redox process activate PS to produce more free radicals, thus improving the performance of the Vis-10 %Ag/ZFO-PS system for phenol degradation. The possible mechanism of the Vis-10 %Ag/ZFO-PS system for phenol degradation is described based on trapping tests, EPR, and XPS results. Magnetic retrievability, good structural stability, and high activity of the synthesized Ag/ZFO photocatalyst elucidate its potential application for degradation of phenolic wastewater.